The invention relates to an apparatus for the production of coatings of uniform thickness profile on substrates, especially by cathode sputtering, consisting of a coating chamber, a sputtering cathode held fixedly in the latter, and a substrate carriage held and guided on rails and/or between slides or rolling bodies and moving through the coating chamber across the sputtering cathode.
An apparatus is known (DE-OS No. 33 06 870), consisting of a sputtering cathode and substrate holders on a common chassis which can travel with respect to the sputtering cathode while performing a continuous rotatory movement of the substrate holders. For this purpose a driving wheel is disposed on the chassis with its axis of rotation perpendicular to the direction of travel, a driving means being disposed parallel to the direction of travel, with which the driving wheel is in engagement on a portion of its way, and the driving wheel being coupled to a substrate holder. The driving means is in the form of an endless chain which is carried on two sprockets situated in tandem in the direction of travel, and, by means of a motor, it can be made to circulate, each driving wheel cooperating with a substrate holder through a bevel gear drive.
This known apparatus has the disadvantage, among others, of being extremely complicated and bulky and at the same time not very reliable in operation.
It is the object of the present invention to create an apparatus of the above-described type which will operate without mechanical transmission, will permit an especially low type of construction, and will operate without maintenance, so that in no case will it be necessary to open the coating chamber.
This is achieved according to the invention in that one or more substrate disks are mounted rotatably on the substrate carriage, and their axes of rotation are vertical with respect to the plane of movement of the substrate carriage, while on the side of the substrate carriage facing away from the cathode a plurality of magnets arranged in a row are mounted fixedly in the coating chamber with their direction of magnetization perpendicular to the direction of movement of the substrate carriage; the magnetization of each two adjacent magnets is antiparallel, and the magnet row extends in a plane parallel to the direction of movement of the substrate carriage and cooperates with magnetic disks which are fastened on the hub of the substrate disk and whose direction of magnetization is perpendicular to the hub axis.
In an alternative embodiment of the apparatus, one or more substrate disks are rotatably mounted on the substrate carriage on its side facing the cathode, and their axes of rotation are transverse to the plane of movement of the substrate carriage, while on the side of the substrate carriage facing away from the cathode an electromagnet is disposed fixedly in the coating chamber, with a yoke whose pole faces cooperate with a magnetic plate and whose direction of magnetization is perpendicular to the hub axis, and while the pole faces, which are turned toward one another, are disposed parallel to the direction of movement of the substrate carriage.
Advantageously, the substrate carriage is in the form of a substantially rectangular plate on whose upper side a plurality of substrate disks are rotatably mounted, the corresponding pivot shafts being each brought downwardly through bearing bores in the substrate carriage and affixed to magnetic disks which cooperate with magnets of the magnet row or with the electromagnet.
Preferably, not only every substrate disk but also every corresponding magnetic disk is provided with a hub, both of them being joined together co-rotationally by a pivot shaft, each pair of hubs cooperating with a rolling bearing whose cage is held on the substrate carriage.
In order to produce a disk current that will be especially effective in the sense of rotation of the substrate disks, the row of magnets extending lengthwise of the direction of movement of the substrate carriage is so disposed that the magnetic disks move directly and at a short distance past the individual magnets on their way through the coating chamber.
The row of magnets is best disposed laterally beside the magnetic disk rotating with the hub and immediately underneath the substrate carriage and parallel to the latter.